refactor(task): move schedulers and startup/shutdown task into tasks directory

app/tasks/beatmapset_update.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from datetime import datetime, timedelta
+
+from app.dependencies.scheduler import get_scheduler
+from app.service.beatmapset_update_service import service
+from app.utils import bg_tasks
+
+SCHEDULER_INTERVAL_MINUTES = 2
+
+
+@get_scheduler().scheduled_job(
+    "interval",
+    id="update_beatmaps",
+    minutes=SCHEDULER_INTERVAL_MINUTES,
+    next_run_time=datetime.now() + timedelta(minutes=1),
+)
+async def beatmapset_update_job():
+    if service is not None:
+        bg_tasks.add_task(service.add_missing_beatmapsets)
+        await service._update_beatmaps()